English
Related papers

Related papers: On the fundamental group scheme of rationally chai…

200 papers

(On the fundamental group of rationnally connected varieties.) I show that the fundamental group of a normal variety which is rationally chain connected is finite. The proof holds in non-zero characteristic. Je d\'emontre que le groupe…

Algebraic Geometry · Mathematics 2007-05-23 Antoine Chambert-Loir

It was recently proven by Esnault, Shusterman and the second named author, that the \'etale fundamental group of a connected smooth projective variety over an algebraically closed field $k$ is finitely presented. In this note, we extend…

Algebraic Geometry · Mathematics 2023-05-29 Marcin Lara , Vasudevan Srinivas , Jakob Stix

We show that the algebraic local fundamental group of any klt singularity as well as the algebraic fundamental group of the smooth locus of any log Fano variety are finite.

Algebraic Geometry · Mathematics 2019-02-20 Chenyang Xu

In this paper we describe the fundamental group-scheme of a proper variety fibered over an abelian variety with rationally connected fibers over an algebraically closed field. We use old and recent results for the Nori fundamental…

Algebraic Geometry · Mathematics 2020-04-10 Rodrigo Codorniu Cofré

In this talk, I report on three theorems concerning algebraic varieties over a field of characteristic $p>0$. a) over a finite field of cardinal $q$, two proper smooth varieties which are geometrically birational have the same number of…

Algebraic Geometry · Mathematics 2010-04-26 Antoine Chambert-Loir

We show that the finiteness of the fundamental groups of the smooth locus of lower dimensional log Fano pairs would imply the finiteness of the local fundamental group of klt singularities. As an application, we verify that the local…

Algebraic Geometry · Mathematics 2019-02-20 Zhiyu Tian , Chenyang Xu

We introduce the category of finite \'etale covers of an arbitrary schematic finite space $X$ and show that, equipped with an appropriate natural fiber functor, it is a Galois Category. This allows us to define the \'etale fundamental group…

Algebraic Geometry · Mathematics 2021-05-06 J. Sánchez González , C. Tejero Prieto

We prove that a strongly $F$-regular scheme $X$ admits a finite, generically Galois, and \'etale-in-codimension-one cover $\widetilde X \to X$ such that the \'etale fundamental groups of $\widetilde X$ and $\widetilde X_{reg}$ agree.…

Algebraic Geometry · Mathematics 2019-08-14 Bhargav Bhatt , Javier Carvajal-Rojas , Patrick Graf , Karl Schwede , Kevin Tucker

We study finite $p$-subgroups of birational automorphism groups. By virtue of boundedness theorem of Fano varieties, we prove that there exists a constant $R(n)$ such that a rationally connected variety of dimension $n$ over an…

Algebraic Geometry · Mathematics 2018-09-26 Jinsong Xu

We show that the fundamental group of every enumeratively rationally connected closed symplectic manifold is finite. In other words, if a closed symplectic manifold has a non-zero Gromov-Witten invariant with two point insertions, then it…

Symplectic Geometry · Mathematics 2025-08-28 Alex Pieloch

We show that for any given field $k$ and natural number $r\geq2$, every continuous extension of the absolute Galois group $\mathrm{Gal}_k$ by a finite group is the arithmetic fundamental group of a geometrically connected smooth projective…

Algebraic Geometry · Mathematics 2019-10-22 Nithi Rungtanapirom

In this note we generalize Nori's definition of the fundamental group scheme from a rational point to an arbitrary base point so that when we take $X$ to be a field $k$ and the point to be $k\subseteq \bar{k}$ we still get a non trivial…

Algebraic Geometry · Mathematics 2018-11-21 Lei Zhang

We investigate when the fundamental group of the smooth part of a K3 surface or Enriques surface with Du Val singularities, is finite. As a corollary we give an effective upper bound for the order of the fundamental group of the smooth part…

Algebraic Geometry · Mathematics 2007-05-23 J. Keum , D. -Q. Zhang

Let U be an open subset of a unirational variety (or more generally of a separably rationally connected variety). We prove that there is rational curve C in U such that the fundamental group of C surjects onto the fundamental group of U.…

Algebraic Geometry · Mathematics 2007-05-23 János Kollár

Smooth projective varieties $X$ over a finite field $k$ with $CH_0(X\otimes \bar{k(X)})=\mathbb Z$ have a rational point, in particular Fano varieties. We also refer to http://link.springer.de/link/service/journals/00222/tocs.htm where the…

Algebraic Geometry · Mathematics 2015-06-26 Hélène Esnault

Using previous results concerning the rank two and rank three cases, all connected simply connected Cartan schemes for which the real roots form a finite irreducible root system of arbitrary rank are determined. As a consequence one obtains…

Combinatorics · Mathematics 2010-09-01 Michael Cuntz , Istvan Heckenberger

Kobayashi-Ochiai's theorem says us that the set of dominant rational maps to a complex variety of general type is finite. In this paper, we give a generalization of it in the category of log schemes.

Algebraic Geometry · Mathematics 2007-05-23 Isamu Iwanari , Atsushi Moriwak

We prove that globally $+$-regular varieties are rationally chain connected in dimension three and mixed characteristic with residue field characteristic $p>5$. We also introduce a notion of strongly globally $+$-regular, and show that…

Algebraic Geometry · Mathematics 2026-02-20 Emre Alp Özavcı , Zsolt Patakfalvi , Kevin Tucker , Joe Waldron , Zheng Xu

We prove a conjecture of Koll\'ar stating that the local fundamental group of a klt singularity $x$ is finite. In fact, we prove a stronger statement, namely that the fundamental group of the smooth locus of a neighbourhood of $x$ is…

Algebraic Geometry · Mathematics 2021-11-24 Lukas Braun

The smallness is proved of fundamental groups for arithmetic schemes. This is a higher dimensional analogue of the Hermite-Minkowski theorem. We also refer to the case of varieties over finite fields. As an application, we prove certain…

Number Theory · Mathematics 2014-02-03 Shinya Harada , Toshiro Hiranouchi
‹ Prev 1 2 3 10 Next ›